Automatic twin bar-bridge bench piercer mill



Jan. 29, 1952 H. E. GROSS AUTOMATIC IwIN BAR-BRIDGE BENCH PIERCER MILL 2 SHEETS-SHEET l Filed Sept. 3, 1948 la7/vena 2 slams- SHEET 2 H. E. GROSS AUTOMATIC TWIN BAR-BRIDGE BENCH PIERCER MILL Jan. 29, 1952 Filed sept. 3, 1948 Patented Jan. 29, 1952 AUTOMATIC TWIN BAR-BRIDGE "BENCH TIERCER MILL Harry E. Gross, Lorain, Ohio, assignor to, United States Steel Company, a corporation of New VJersey Application September 3, 1948, Serial No. 47,647

3 Claims.

This invention relates to an automatic twinbar bridge bench piercer mill and more particularly to such a mill having a pivotally mounted bottom piercer guide.

Prior to my invention, conventional piercing mills were equipped with a Vsingle plug-bearing thrust bar on the delivery side of the mill. In the operation of a single bar piercing mill the thrust bar is withdrawn through the pierced shell in `order to permit the shell to be removed for asubsequent operation. As the bar is withdrawn, the piercer plug on its end is detached and remains in the `roll pass. The used plug is then too hot to be used for piercing another billet and therefore `must be removed from the roll pass for cooling. This removal is ,ordinarily accomplished manually with the aid of a pair of tongs. In order to proceed `with operations a fresh `plug is placed on the single thrust bar and positioned within the roll pass. Although the time consumed during each plug change is short, the repeated plug changes necessary have a serious cumulative effect `on the number of `shells the mill is capable of producing within a given period of time. This limitingiactor Ais a Vcommon characteristic inherent yin all single thrust bar piercing mills and is one which Acannot be overcome by the` usual measures, `suchfas increasing the operating speed of the mill orren- .Another factor which eiects piercing mill pro- I duction is the tendency for some shells to become lodged Within the roll housing after the piercing operation, so that manual manipulation is necessary to loosen them before operations `can continue.

I propose to increase seamless tube `shell production substantially by providing a piercing mill that is free of the detrimental characteristics `described above. tion is equipped with two plug-bearing thrust bars positioned adjacent to each other and so adapted that each may be alternately operated in the piercing roll pass while the other remains in stand-by position. While the one thrust bar is operating the other can vbe prepared in its stand-by position for the next billet piercing operation. In conjunction with this `feature I propose to also provide an automatic plug discharge-means inthe .mill which will .eliminate The piercing'mill of my invenl* entirely the need for any manual handling inthe plug removal process. The mill I propose is also provided with positive means for pulling lor :1delivering the pierced shell from the roll housing to the bridge bench, thus insuring unimpeded passage for each shell and eliminating mill delays due to shells becoming lodged within the roll housing.

It is, accordingly, an object ofmy invention to provide an automatic twin-bar bridge bench piercing mill, for seamless tube production, that is capable of increased production through the use of new automatic movement controls and operations.

It is another object of my invention to provide a piercing mill having a bottom drop guide support for automatically discharging a used plug 'from the mill roll pass,

It is a further object of my invention to provide a piercing mill having pull-out rolls for engaging the pierced shells on the outlet side of the :coll pass of said mill.

These and other objects will become more apparent after referring to the following specication and attached drawings, in which:

Figure 1 is a top plan View of a mill embodying my invention;

Figure 2 isa side elevation; i Figure 3 is a central vertical section showing .the pivotally mounted bottom guide support and safety gate;

Figure 4 is a sectional view taken on the line `IV-IV of Figure 2; and

Figure 5 is a sectional view taken on the lin V--V of Figure 2. i

Referring more particularly to the drawings, a bridge bench 2 moves transversely on the delivery side of piercing mill rolls 20, 20f on wheels 4 over rails 6. The bridge bench transverse drive 8 comprises a motor I0 which through gears I2 `and through a shaft I4 drives pinions I6 which actuate rack bars I8. The bench 2 supports two water-cooled thrust bar units 22 and 24, complete vvith pulley drives 26 and 28, mounted on shafts 38 and 32 which are rotated through gears 34 and 36 by motors 38 and 4U. A drop latch 4I is provided for holding each thrust bar in piercing position. Run outs 42 and 44 and bottom dump troughs 46 and 46 are also provided on the delivery side of the mill. troughs 46, 46 are operated `by air cylinders 4B, 4B which open and close sides '50, 56' of each trough through rack and ypinion connections 52,522 Bridge bench 2 is Vsupported longitudinally by a thrust ypier `54. ,A lower .floor chain Bottom dump l conveyor 56 is provided beneath the bottom dump troughs 46, 46' for carrying the pierced shells 58 transversely to the next operation.

A pair of pull-out rolls 60 is provided adjacentl the delivery side of rolls 20, 20 for engaging a workpiece W as it clears over a piercing plug 62 in the roll-pass. Rolls 60 are driven through gears 64 by vertical motors 66'.

Supporting a bottom guide shoe 68, in the roll pass between rolls 20, 20, is a drop guide support l pivotally mounted at l2. The guide support I0 is provided with an inclined bottom surface Y'14, an extended portion I6 at its upper forward end, a vertical abutment '|'8 projecting from its upper surface 16, and a downwardly extending lug portion 80 at its inner end. The guide shoe 68 rests on a iiller plate 82 disposed on the upper surface 19. A vertical clamp bar 84, pivotally mounted on the extended forward portion 16 of the guide support 10, serves to draw Vtogether the guide shoe 68, ther guide support l0 and the filler plate 82. The clamp bar 64 is, in turn, pulled tightly against the guide shoe 68 and ller plate 62 by means of a forked clamp bolt 86 which extends longitudinally through guide support l0 and projects outwardly from its lug portion 06. The clamp bolt V|36'is held in position by means of two lock nuts 88 which are threaded on its projecting inner end.

Guide support 'l0 is actuated by means of a bar wedge B0 which, in turn, is actuated by a two-way pressure cylinder 92. Rotatably mounted in a recess 94, in the top surface of bar wedge 90, is an idler roll 95 which rolls along the inclined bottom surface 14 of guide support 10 as the bar wedge 90 slides along a rail 96 below the guide support. The forward stroke position of the bar wedge is limited by a vertically hooked end 96 on the forward end |00 of rail 96. The position of the hooked end 98 is controlled by means of a wheel |02, which turns on a threaded bar |04 secured to rail 96, for remote adjustment of bottom drop guide support '10.

In order to prevent the billet W from entering the roll pass between rolls 20, 20 when the guide support `'l0 is not inv working position, a safety gate |06 is provided before the entrance end of the roll pass. Gate |06 is actuated by. cables |68 which pass over pulley ||0 and are connected to a cable hook ||2 affixed to bolt 66 intermediate the lock nuts 88. This arrangement provides for automatic movement of safety gate |06 in connection with the movement of guide support l0, the gate being automatically lowered to block the entrance to the roll pass when guide support l0 is lowered out of position and then being raised when the guide support is raised into Working position.

lAn inclined chute |4 is 'provided to receive the used plug 62 when the guide support 'I0 is lowered after each piercing operation has been completed. The lower end of chute |l4 is disposed above a continuous chain conveyor |6 which is submerged in a water box I8. Extending upwardly fromthe discharge end of conveyor EB is an elevator conveyor |20 having its lower end submerged in the water box H6 for the purpose of receivingthe used plug and carrying it upwardly to a spiral chute |22, whereby it is returned to a plug storage box |24 located on the plug mans platform |26. Plug box |24 is positioned so as to be easily accessible to the plug man for preparing the thrust bar in stand-by position. The plug bridge bench 2 where it is picked up by the thrus bar advancing to stand-by position.V

' pass.

In operation, the workpiece W is charged into piercer rolls 20, 20 by means of a conventional billet charger. At the beginning of operations, guide support 10 is in working position and safety gate |06 is, therefore, in raised position. As

shown in Figure 1, the end of thrust bar 24, carrying plug 62, is positioned in the roll pass between rolls 20, 20. After the workpiece has been pierced, it will be engaged by pull-out rolls 60, as it clears over plug 62, to advance it on to the bottom dump trough 46. When the thrust bar 24 is Withdrawn from its Working position in the roll pass the piercer plug 62 is detached from the bar and remains on the guide shoe `66 within the roll After the thrust bar is withdrawn from workpiece W, air cylinders 48 open the side 50 of trough 46' causing the shell to drop onto conveyor 56 which carries it transversely to the next operation. Meanwhile, cylinder 92 is actuated to withdraw the bar wedge from its forwardposition which withdrawal causes guide support 'I0 to drop from working position and the safety gate |66 to lower into position, blocking the entrance to the roll pass. Upon dropping guide support '10, the piercer plug 62 slides onto the chute ||4 and hence onto conveyor ||6 which transfers it horizontally to elevator conveyor |20. The conveyor ||6 and the lower end of conveyor |20 are both submerged in water box ||B so that the plug is cooled thereby. The cooled plug, elevated on conveyor |20, drops onto the spiral return chute |22 and from there into the plug storageV box |24.

After the plug 62 has been dropped onto chute ||4, bar wedge 90 is again advanced forward to raise guide support l0 into working position. This movement causes safety gate |06 to be automatically raised out of blocking position so that another billet can enter the roll pass. Bridge bench 2, meanwhile, has been moved transversely and thrust bar 22, bearing plug 62', has advanced into working position in the roll pass. While thrust bar 22 is in working position a fresh plug will be placed on the bridge bench 2 and thrust bar '24 will be advanced by pulley drive 26 to stand-byposition to pick up the plug. It remains in this stand-by position preparatory to moving intoworking position for piercing the next billet afterthrust bar 22 is withdrawn.

While one embodiment of my invention has been shown and described it will be apparent Ythat other adaptionsand modifications may be made without departing from the scope of the following claims.

I claim;

l. Plug-handling apparatus for a piercer mill comprising a guide-shoe support pivotally mounted below the mill, a guide shoe on-said support, said guide shoe being positioned to catch la piercing plug on withdrawal of the thrust bar therefrom, means for raising and lowering said guideshoe support, a gate suspended adjacent the entrance side of the mill, and means connecting said gate with said support for operation thereby when said support is raised and lowered. 2. A bottom guidefor a tube piercer mill comprising a guide-shoesupport pivotallymounted below the mill, a longitudinal rail below said support, a wedge bar slidingly mounted on Vsaid rail, a roller journaled in said wedge bar and engaging'said support, and means for reciprocating said bar over said rail to thereby raise and lowerV said support. Y

3. In a piercing mill, the combination with a bottom guide support pivotally mounted below the 5 mill, means for raising and lowering the support, a safety gate on the entrance side of the mill and a connection from the support to the gate whereby the gate is moved to an out-of-the-way position when the support is raised.

HARRY E. GROSS.

UNITED STATES PATENTS Name Date Stiefel et a1 Sept. 13, 1904 Number Number Number Name Date Brock et al 1 Mar. 19, 1912 Nowak Aug. 20, 1912 Wikstrom May 12, 1925 Lowy June 17, 1930 Olson July 25, 1933 Bark et al. June 18, 1935 Diescher July 2, 1935 Westin et al 'Mar. 6, 1945 FOREIGN PATENTS Country Date Great Britain Jan. 30, 1930 

